Increasing intensity of standing calf raise machine once you max out the weight?

I've been doing normal form where I'm standing up straight, and have maxed out on the weight possible for the machine. I would switch over to dumbbells and a step, but I don't think I can safely move/hold onto dumbbells that heavy.

I've just been adding a rep to my 3 sets every time, but I'm wondering if there are ways to increase the intensity otherwise? I can hit the max weight with all angles of my feet, so I've already tried that. Thanks